It is proposed to investigate the appearance of specific antibodies in the oviductal fluid, their possible variations during the ovulatory cycle, and the correlation with the level of circulating serum antibodies in rhesus monkeys under experimental conditions that are as closely as possible related to physiological conditions. Special attention will be paid to the time of ovulation because of its important relationship to processes involved in fertilization. It is planned to collect oviductal fluid continuously into constantly refrigerated collection chambers after surgical cannulation of the oviducts over periods of 8-12 days. Ovulation will be induced with human menopausal gonadotropins and human chorionic gonadotropin. During the initial phases of the studies, a model antigen, i.e. T4-coliphages will be used to immunize female rhesus monkeys systematically and also locally (vaginally). The very sensitive phase neutralization antibody test will be utilized to study the immune response. During the later phases of the investigations the female rhesus monkeys will be immunized with allogeneic spermatozoal antigens and the immune response will be studied in the oviductal fluid and in serum. Attempts will be made to compare the patterns of antibody secretion in the oviductal fluid and in the cervical secretion. The results of this study will provide basic information for the better understanding of the immune system of the female genital tract in primates. This has implications for the elucidation of immunological interference (experimental and clinical) with fertilization and early development of the conceptus as well as for infections of the internal female genital tract.